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Anaphoric Macro
An anaphoric macro is a type of programming macro that deliberately captures some form supplied to the macro which may be referred to by an ''anaphor'' (an expression referring to another). Anaphoric macros first appeared in Paul Graham's '' On Lisp'' number 3) number) when true, collecting numbers larger than 3: number 3) number) collect it) ; IT refers to (and (> number 3) number). ;; ⇒ (4 5 6) Defining anaphoric macros One example is an anaphoric version of the if-then-else construct, which introduces an ''anaphor'' it, bound to the result of the test clause:Chapter 14. Anaphoric Macros of On Lisp by [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Macro (computer Science)
In computer programming, a macro (short for "macro instruction"; ) is a rule or pattern that specifies how a certain input should be mapped to a replacement output. Applying a macro to an input is known as macro expansion. The input and output may be a sequence of lexical tokens or characters, or a syntax tree. Character macros are supported in software applications to make it easy to invoke common command sequences. Token and tree macros are supported in some programming languages to enable code reuse or to extend the language, sometimes for domain-specific languages. Macros are used to make a sequence of computing instructions available to the programmer as a single program statement, making the programming task less tedious and less error-prone. (Thus, they are called "macros" because a "big" block of code can be expanded from a "small" sequence of characters.) Macros often allow positional or keyword parameters that dictate what the conditional assembler program generates ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anonymous Function
In computer programming, an anonymous function (function literal, lambda abstraction, lambda function, lambda expression or block) is a function definition that is not bound to an identifier. Anonymous functions are often arguments being passed to higher-order functions or used for constructing the result of a higher-order function that needs to return a function. If the function is only used once, or a limited number of times, an anonymous function may be syntactically lighter than using a named function. Anonymous functions are ubiquitous in functional programming languages and other languages with first-class functions, where they fulfil the same role for the function type as literals do for other data types. Anonymous functions originate in the work of Alonzo Church in his invention of the lambda calculus, in which all functions are anonymous, in 1936, before electronic computers. In several programming languages, anonymous functions are introduced using the keyword ''lambda' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Programming Constructs
Program, programme, programmer, or programming may refer to: Business and management * Program management, the process of managing several related projects * Time management * Program, a part of planning Arts and entertainment Audio * Programming (music), generating music electronically * Radio programming, act of scheduling content for radio * Synthesizer programmer, a person who develops the instrumentation for a piece of music Video or television * Broadcast programming, scheduling content for television * Program music, a type of art music that attempts to render musically an extra-musical narrative * Synthesizer patch or program, a synthesizer setting stored in memory * "Program", an instrumental song by Linkin Park from '' LP Underground Eleven'' * Programmer, a film on the lower half of a double feature bill; see B-movie Science and technology * Computer program, a set of instructions that describes how to perform a specific task to a computer. * Computer programmi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lisp (programming Language)
Lisp (historically LISP) is a family of programming languages with a long history and a distinctive, fully parenthesized prefix notation. Originally specified in 1960, Lisp is the second-oldest high-level programming language still in common use, after Fortran. Lisp has changed since its early days, and many dialects have existed over its history. Today, the best-known general-purpose Lisp dialects are Common Lisp, Scheme, Racket and Clojure. Lisp was originally created as a practical mathematical notation for computer programs, influenced by (though not originally derived from) the notation of Alonzo Church's lambda calculus. It quickly became a favored programming language for artificial intelligence (AI) research. As one of the earliest programming languages, Lisp pioneered many ideas in computer science, including tree data structures, automatic storage management, dynamic typing, conditionals, higher-order functions, recursion, the self-hosting compiler, and the read†... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
This (computer Programming)
this, self, and Me are keywords used in some computer programming languages to refer to the object, class, or other entity of which the currently running code is a part. The entity referred to by these keywords thus depends on the execution context (such as which object is having its method called). Different programming languages use these keywords in slightly different ways. In languages where a keyword like "this" is mandatory, the keyword is the only way to access data and methods stored in the current object. Where optional, they can disambiguate variables and functions with the same name. Object-oriented programming In many object-oriented programming languages, this (also called self or Me) is a variable that is used in instance methods to refer to the object on which they are working. The first OO language, SIMULA 67, used this to explicitly reference the local object. C++ and languages which derive in style from it (such as Java, C#, D, and PHP) also generally use ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Method Chaining
Method chaining, also known as named parameter idiom, is a common syntax for invoking multiple method calls in object-oriented programming languages. Each method returns an object, allowing the calls to be chained together in a single statement without requiring variables to store the intermediate results. Rationale Local variable declarations are syntactic sugar. Method chaining eliminates an extra variable for each intermediate step. The developer is saved from the cognitive burden of naming the variable and keeping the variable in mind. Method chaining has been referred to as producing a "train wreck" due to the increase in the number of methods that come one after another in the same line that occurs as more methods are chained together. A similar syntax is method cascading, where after the method call the expression evaluates to the current object, not the return value of the method. Cascading can be implemented using method chaining by having the method return the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hygienic Macro
Hygienic macros are macros whose expansion is guaranteed not to cause the accidental capture of identifiers. They are a feature of programming languages such as Scheme, Dylan, Rust, Nim, and Julia. The general problem of accidental capture was well known within the Lisp community prior to the introduction of hygienic macros. Macro writers would use language features that would generate unique identifiers (e.g., gensym) or use obfuscated identifiers in order to avoid the problem. Hygienic macros are a programmatic solution to the capture problem that is integrated into the macro expander itself. The term "hygiene" was coined in Kohlbecker et al.'s 1986 paper that introduced hygienic macro expansion, inspired by the terminology used in mathematics. The hygiene problem Variable shadowing In programming languages that have non-hygienic macro systems, it is possible for existing variable bindings to be hidden from a macro by variable bindings that are created during its expansion ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anonymous Recursion
In computer science, anonymous recursion is recursion which does not explicitly call a function by name. This can be done either explicitly, by using a higher-order function – passing in a function as an argument and calling it – or implicitly, via reflection features which allow one to access certain functions depending on the current context, especially "the current function" or sometimes "the calling function of the current function". In programming practice, anonymous recursion is notably used in JavaScript, which provides reflection facilities to support it. In general programming practice, however, this is considered poor style, and recursion with named functions is suggested instead. Anonymous recursion via explicitly passing functions as arguments is possible in any language that supports functions as arguments, though this is rarely used in practice, as it is longer and less clear than explicitly recursing by name. In theoretical computer science, anonymous recursion ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Recursion (computer Science)
In computer science, recursion is a method of solving a computational problem where the solution depends on solutions to smaller instances of the same problem. Recursion solves such recursive problems by using functions that call themselves from within their own code. The approach can be applied to many types of problems, and recursion is one of the central ideas of computer science. Most computer programming languages support recursion by allowing a function to call itself from within its own code. Some functional programming languages (for instance, Clojure) do not define any looping constructs but rely solely on recursion to repeatedly call code. It is proved in computability theory that these recursive-only languages are Turing complete; this means that they are as powerful (they can be used to solve the same problems) as imperative languages based on control structures such as and . Repeatedly calling a function from within itself may cause the call stack to have a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Conditional (programming)
In computer science, conditionals (that is, conditional statements, conditional expressions and conditional constructs,) are programming language commands for handling decisions. Specifically, conditionals perform different computations or actions depending on whether a programmer-defined boolean ''condition'' evaluates to true or false. In terms of control flow, the decision is always achieved by selectively altering the control flow based on some condition (apart from the case of branch predication). Although dynamic dispatch is not usually classified as a conditional construct, it is another way to select between alternatives at runtime. Terminology In imperative programming languages, the term "conditional statement" is usually used, whereas in functional programming, the terms "conditional expression" or "conditional construct" are preferred, because these terms all have distinct meanings. If–then(–else) The if–then construct (sometimes called if–then–els ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paul Graham (computer Programmer)
Paul Graham (; born 1964) is an English-born American computer scientist, essayist, entrepreneur, venture capitalist, and author. He is best known for his work on the programming language Lisp, his former startup Viaweb (later renamed ''Yahoo! Store''), cofounding the influential startup accelerator and seed capital firm Y Combinator, his essays, and Hacker News. He is the author of several computer programming books, including: ''On Lisp'', ''ANSI Common Lisp'', and '' Hackers & Painters''. Technology journalist Steven Levy has described Graham as a "hacker philosopher". Education and early life Graham and his family moved to Pittsburgh, Pennsylvania in 1968, where he later attended Gateway High School. Graham gained interest in science and mathematics from his father who was a nuclear physicist. Graham received a Bachelor of Arts in philosophy from Cornell University (1986). He then attended Harvard University, earning Master of Science (1988) and Doctor of Philosophy (1990) ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Common Lisp HyperSpec
The Common Lisp HyperSpec is a technical standard document written in the hypertext format ''Hypertext Markup Language'' (HTML). It is not the American National Standards Institute (ANSI) Common Lisp standard, but is based on it, with permission from ANSI and the International Committee for Information Technology Standards (INCITS, X3). Originally developed by Kent Pitman at Harlequin, it is now copyrighted by LispWorks Ltd. It is approximately 15 megabytes (MB) of data in 2,300 files which contain approximately 105,000 hyperlinks. The HyperSpec is used by many Common Lisp development environments (examples: LispWorks, the Superior Lisp Interaction Mode for Emacs (SLIME) for looking up reference information on the constructs of ANSI Common Lisp. The HyperSpec is also available for download. Before the ANSI Common Lisp standard, the book ''Common Lisp the Language'' had been used as a Common Lisp standard reference. Allegro Common Lisp Allegro Common Lisp is a programming langua ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
